The present invention generally relates an apparatus and method for securing suture to bone, and more particularly, to suture anchors for securing soft tissue to bone.
When soft tissue tears away from bone, reattachment becomes necessary. Various devices, including sutures alone, screws, staples, wedges, and plugs have been used in the past to secure soft tissue to bone.
Recently, various types of threaded suture anchors have been developed for this purpose. Some threaded suture anchors are designed to be inserted into a pre-drilled hole. Other suture anchors are self-tapping.
U.S. Pat. No. 4,632,100 discloses a cylindrical threaded suture anchor. The suture anchor of the ""100 patent includes a drill bit at a leading end for boring a hole in a bone, followed by a flight of threads spaced from the drill bit for securing the anchor into the hole created by the drill bit. U.S. Pat. No. 5,370,662 discloses a suture anchor having a flight of threads which extend to the tip of the anchor. U.S. Pat. No. 5,156,616 discloses a similar suture anchor having an axial opening for holding a knotted piece of suture.
All of the above-noted suture anchors include structure for attaching the suture to the anchor. U.S. Pat. No. 4,632,100, for example, discloses and claims a press-fitted disc and knot structure which secures the suture to the anchor. In other suture anchors, such as those disclosed in U.S. Pat. No. 5,370,662, the suture is passed through an eyelet located on the proximal end of the anchor. U.S. Pat. No. 5,152,790 discloses a suture anchor with a rotatable ring for securing suture to the suture anchor.
The devices discussed above are fairly time consuming and complicated to fasten the soft tissue against the bone mass. It is also difficult for these devices to keep the soft tissue tightly attached to the bone mass during the body""s healing process.
It would therefore be an advantage to provide a suture anchor that simplifies the operation process and effectively secures the soft tissue against the bone mass during the body""s healing period. Preferably, the suture anchor will be provided with an eyelet that is movable with respect to the anchor in order to simplify the process of attaching a suture to the eyelet.
In response, the present invention provides suture anchor for securing soft tissue to bone, including a body having opposing first and second ends, a longitudinal axis extending between the ends, an external threaded portion extending from the first end, and a bore extending from the second end towards the first end. The body also has a first pair of slots extending laterally outwardly from the bore and extending longitudinally to a predetermined first distance from the second end, and a second pair of slots extending laterally outwardly from the bore and extending longitudinally to a predetermined second distance from the second end.
The anchor additionally includes an eyelet receivable within the first and the second pairs of slots of the body and having an opening for receiving a suture, and a spring biasing the eyelet into the bore.
According to one aspect of the present invention, the first distance is sized to maintain the opening of the eyelet at least partly out of the bore, and the second distance is sized to allow the spring to bias the eyelet further into the bore. According to another aspect, the second distance is sized to allow the spring to bias the entire eyelet into the bore.
According to an additional aspect, the spring comprises a tension spring disposed along the axis within the bore and having a first end attached to the body member and a second end attached to the eyelet. According to a further aspect, the tension spring is helical. According to still another aspect, the bore of the body includes a socket, and the spring includes a mooring extending from the first end of the spring and secured in the socket for rotation therein.
The present invention provides another suture anchor for securing soft tissue to bone. The anchor includes a body member having a first end and a second end, a central axis extending between the first and the second ends, an external threaded portion coaxial with the central axis extending from the first end, and a bore extending coaxial with the central axis from the second end to a socket adjacent the first end. The anchor also includes an insert having a mooring secured in the socket, a shaft extending within the bore from the mooring towards the second end of the body member, and an eyelet secured to the shaft and having an opening for receiving a suture.
According to one aspect, the insert can be rotated with respect to the body member. According to another aspect, the insert can be moved vertically with respect to the body member.
These and other features and advantages of the present invention will be more fully appreciated with reference to the following detailed description which is to be read in conjunction with attached drawings.